平面偏振光场光弹性实时相移法

Photoelasticity real-time phase-shifting method in plane polariscope

光弹性法可广泛用于二维、三维应力或应变场的研究。根据偏振相移法的原理,提出一种新的积分相移法,并设计了用于全场等倾线和等差线实时分析的光弹性仪。在正交偏振光场下,按一定速度同步旋转起偏镜和分析镜,CCD摄像机可连续获取四幅相移光弹图像,由CCD像敏单元积分获得其光强值,通过所提出的相移法运算,可以迅速地得出全场等倾角和等差线的相位值。该方法和装置不仅可用于光学原件及玻璃制品的高速检测,而且也可用于随时间缓慢变化的光弹性分析中。

Photoelasticity is applied in two- and three-dimensional stress analysis widely. A new integrating phase-shifting method is proposed to analysis of isochromatic and isoclinic parameters, and a new type digital photoelasticity real-time automat- ic collection system is developed. In the crossed plane polariscope, by rotating the polarizer and the analyser at constant rate in synchronism and recording images by a CCD camera continuously, four phase-shifted images whose intensity are integrated by sensors are obtained. Then, the distribution of the isoclinic and the isochromatic parameter are obtained speedy using the pro- posed phase-shifting algorithm. The proposed method and system can be applied to high-speed inspection of optical elements or glass products. Also, it is expected that slowly varying time-dependent problems can be analyzed by the proposed method.